I prefer boxer briefs. They're comfortable and hold things in place. Make sure you get some with at least 5% spandex, though. Otherwise they'll end up stretching out and fitting more like boxers after just a few hours. So probably wanna pass on the Hanes and Fruit Of The Loom. When it comes to underwear, you get what you pay for.

yeah, what they said. If you are not packing boxers are fine, but if you want a packer to stay in try briefs or boxer briefs.

I found that if you buy cheap boxer briefs, you will have to wear a harness.  However, if  I buy expensive boxer briefs, I can get away without the harness.  Also, cotton stretches!  My most recent were Jokey Pro Midway Boxer Briefs.  They don't ride up, keep everything where it belongs, are super soft and comfortable all day.  The run about $14 if you buy in a two pack.  Any that I tried that were less than $10 a pair required a harness or some other way of supporting things.  I do not like briefs at all and boxers don't support anything.